fix(bower): remove direct references to jquery.d.ts file in pow-core
fix(bower): remove direct references to jquery.d.ts file in pow-core

 - Conflicting d.ts files can cause errors when including in projects that use the same vendor library's d.ts in their project.
 - Add template accessors on affected classes to allow specialization during usage to comply with project's existing type files.

justindujardin/pow-core,justindujardin/pow-core